Automatic safety rail clamp



Aug 17, 1943. ZAVATKAY 2,327,325 Q AUTOMATIC SAFETY RAIL CLAMP Filed Aug. 26, 1941 5 Sheets-Sheet 1 ATTORNEYS.

Aug. 17, 1943.- F. F. ZAVATKAY AUTOMATIC SAFETY RA IL CLAMP 3 Sheets-Sheet 2 Filed Aug. 26, 1 941 NVENTOR ATTORNEYS.

Patented Aug. 17, 1943 Fredcrick F. Zavatkay, New Haven, Conn. Application August 26, 1941, Serial No. 408,324

11 Claims. (01. 188-43) This invention relates to a safety device for traveling cranes and cars, especially railway locomotive cranes or all' cranes and cars traveling on rails, and particularly to safety clamps carried by the crane or car which may b clamped on the track rails to hold the crane or' car from tipping over when an attempt is made to lift or handle too great a load. It has for an object to provide an improve construction of clamp which may be mounted one at each'of the four corners of the crane or car for gripping the track rails, and which may be set or released by a simple operation of the crane operator. It is also an object toprovide such a c0nstruction with control means which is interconnected with brake controlmeans for the car so that the brakes must be set before setting the clamps, and

also the'clamps must-be released before releas ing the brakes so there is no danger of starting the car until the clamps are released. I I

A- further object is to provide an improved construction of clamp and operating meanstherefor so that the pull on. the clamp is independent of the operating meansand it is'al straight-up ward pull.

Another object is to. provide a device in com bination with such clamping or holding means which can be set for different .loads and different radii of th crane boo-m, to. indicate the,

proper load at such radii, and if the load exceeds it then to automatically ound an alarm;

to indicate this fact to the operator.

;With the foregoing and other objects in view I have devised the construction. illustratedin the accompanying drawings forming a part. of this specification, it being understood, however, that I am not limited to thespecific' constructionand arrangement showngbut may employ various changes and modifications within the scope of the invention. The drawings are made showing the Fig. 3 is aside elevation of the clamps andtheir operating means at one end of the car;

Fig. 4 is a partial section and a partial elevation of a portion of the indicating mechanism; Fig.j5 is a section thereof substantially on line 5-5 of Fig. 4;

Fig. 61is an elevation looking from the right of Fig. 3, and

application of the invention applied to alocomotive crane, but this particular application is used merely for illustration as the invention may bev applied to any form. of crane traveling. on rails.

It could also be applied to railway cars orany cars traveling on rails.

Inthese drawings: f v I V Fig. 1 is a partial side elevation and partial section, but principally a diagrammatic-view, showing the general layoutof the device on a railway locomotive crane; V

Fig. 2 is a side 'elevationon a larger scaleshown ing the interlocking control between the brake control mechanism and theclamp control;

Fig. 7 is a partial section and partial diagrammatic View of the control mechanism for the clamps. V I

These railway locomotive cranes as generally constructed comprise a body including a bedplate ortruck bed I0 m'ountedon suitable trucks 2 with wheels, not shown. running on the track rails H, and they maybe single or double trucks using four or six wheels. Mounted to turn on this bed is a rotating bed or platform {2, the pivotal connection l3 between th platform. and the bed being indicated diagrammatically at l3, Fig. 1 and this connection is hollow so that, a steam, air or other control-pipe or conduit [4 can pass through it for operating the brakesffor the car and the clamps for preventing tipping l of the car, this pipe connection comprising of course a suitable swivel joint to permit turning of the platform and other mechanism carried thereby relative to the bed IO- in the operation of the crane. The mechanism'for turning the plat-.

form and the crane lifting mechanism are not shownas they form no part of the present invention.

Mounted onthe bed Ii), preferably one at each 1 of the four corners, is a clamp l5 capable of gripping the rails H and so connected to the bed In that should attempt be made to lift a greater load than the maximum .capacity... for which the crane is designed at various angles of the boom, which would otherwise tip the car beyond a desired amount or even tip it over, a clamp or clamps will hold it and prevent tipping beyond a certain limit. These clamps; are mounted and constructed with a suitable control mechanism in the cab 9 of the crane so that the crane operator can set these clamps before operating the crane to thus obviatedang'er of tipping over the crane in use, which action can easily happenwithout these devices unless extreme caution is observed. Serious accidents have resulted from this.

The clamp mechanism, shown more clearly in Figs-,3 and 6, may'be arranged so that one power operated device may operate the two clamps at each end of the car-or bed located vat the two opposite corners to clampthetwo rails ll of the of the device of Fig. a

. stop nut 29 and a lock nut 30.

track. In the arrangement shown in Fig. 3 each clamp l5 comprises a pair of jaws [6 adapted to grip under the top flange or tread I! of the track rails H, and each jaw forms one arm of a lever !8 two of which are pivoted together at l9, and this pivot also mounts them in the forked head 28 of the rod 2|. A link 23 is pivoted at 24 to the other arm 22 of each of the levers i8 and at their other ends these two links are pivoted together at 25 and to a connecting member 26, this pivot 25 being also slidable in a longitudinal slot 21 in the head 26 above the pivot is. The upper end portion of the rod 2! is slidable in a guide bracket 28 mounted on the bed It and is threaded at its upper end to receive an adjustable The other end of the connecting member 26 is, pivotally connected at 3| to one arm of a lever 32 pivotally mounted at 33 on a supporting bracket 34 connected to the bed by suitable means such as the bolts 35. The other arm-36 of this lever 32 is pivotally connected at iil' to link 38 the other end of which is pivotally connected at 39 to the head 40 mounted on a piston rod 4| connected to a piston (not shown) in'an operating cylinder 42. This cylinder is also supported by the bracket 34.

These clamps are shownin full lines in in clamped position gripping the rails H. V In the dotted lines at the lefthand o'f Fig.3 the parts are shown in their positions with the clamps unlocked from the rail, not raised, while in the dotted lines at the right hand of Fig. 3 the clamps and the associated mechanism are shown raised in position for thetravel of the car. They may be held and locked in this position byany suitable means, a'very simple means being to drill atransverse h'ole l3 in therod in a suitable position so that when raised it will be above the guide bracket .28 and may receive 'a'locking pin 44 which when inserted in this opening by resting on top of the bracket 28 'will'hold the rod and the jaWs connected thereto inthe elevated position independently of the cylinder 42 and its piston. a 7

Associated with each clamp is an indicating means and alarm for warning the operator when the proper load-has been exceeded. Mounted on the bed it], either separately or associated with the; bracket 25, is a scale d5, and adjustably mounted on this scale is a pointer 45 insulated from the support and including a resilient fibre washer 4:? (Fig. 5)., to hold it in adjusted positions. Ina guide 43 is the head roof at slidable rod 59 carrying a contactfzi adapted when shifted to engage the contact 46 to make an electrical connection, the two being connected by lead wires 52 and 5 3 through a'battery 54 to anaudible alarm 55. The lower end of the rod '553 is slidable in an arm 55 carried by the rod 2| with a nut 5'! below it so that the arm 55111134! slide upwardly'on the rod 55, but when moving downwardly beyond a certain limit will-engage the nut 5! to draw the rod'!) downwardly against the action of the spring 58 and therefore shift downwardly the contact E-l toward the contact 56. The spring 58 normally holds the rod 5i! and contact 5! inits upper position unless shifted downward-by the arm 56. The scale45 may be calibrated in feet to indicate different radial positions of the boom of thecrane, and the spring mechanism 58 and asso-ciatcd parts may in conjunction with a scale indicate the tipping capacity of the crane. Therefore when the contact 5| of the spiing mechanism and the contact it of the foot radius scal'eof the boom coincide, an

electric circuit is closed through the alarm 55 giving a warning indication to the operator in the cab that the capacity at that radius has been reached. The scales and contact mechanism 45' to 58 is shown in conjunction With one clamp only for simplicity, but it is understood they will be used with each clamp at each of the four corners of the car.

The mechanism and control for setting and releasing the clamps and the brakes of the car are shown in Figs. 1, 2 and 7. The pipe M may be connected with a supply pipe 55 of a train steam line or air line through a brake control valve GI and from which may lead an exhaust pipe 52, or

air could be supplied from an independent com- 7 pressor on the crane car operated either by steam or electricity. The clamps may be operated by any suitable power as steam, air, hydraulic or electricity. As shown, the pipe it passes through the pivotal connection l3 to a brake cylinder 63 in which is a piston, not shown, connected'to operate a piston rod 54 connected to the brakes (not shown) of the car for operating them to set.

them against the wheels when pressure is suppliedto the cylinder 63. Of course when the pressure is released in cylinder 83 the brakes will release in the usual manner. A branch pipe 65 leads to a receiver 535 from which another pipe 61 leads to a solenoid controlled valve 68. From this valve lead pipes-69 to the cylinders 42 to supply pressure to operate the cylinders to set the clamps on the rails by raising the piston connected to the piston rod i I. Another pipe line 10 leads from the other end of the valve 68 to the upper part of the cylinders 42 so that when pres sure is supplied it will force the piston connected to the piston rod 4! downwardly to release the clamps and to raise them to the inoperative position, as will be apparent from an inspection of Fi 3.

The solenoid control valve 68 may be of standard construction and purchased on the. market and its operation is shown diagrammatically in Fig. 7. It comprisesa piston valve ll in a cylinder. 12, and when in the position shown in Fig. 7

permits fluid under pressure to pass from supply pipe 6! to pipe 69 to the lower part of the cylinders 42. While in this position it cuts off connection from the pipe 6'! to pipe [0 and permits pressure in this pipe 10 to exhaust. When the valve isshifted to the left to the other position it cuts ofi communicationfrom pipe 6! to pipe 69 and places it in communication with the pipe 10 to supply fluid pressure to the upper end of the cylinders 52. In this position pressure in pipe 69 may exhaust.

The valve H is shifted to the .oppositepositions by the solenoids l3 and it one end of each of which is grounded at 15 and the other end leads to contacts Iii and Ti respectively of the limit switches 78 and 19.

Springs 89 tend to shift these switch members to engage their respective contacts 16 and TI to close the circuit from the supply wire 8! connected to each switch member. Mounted on the valve stems 82 and 83 are rent from the; generator 81 or battery 88 to the supply line 8| to energize the solenoids 13 and I4 to shift the control val've I l. Thisswitch is shown diagrammatically in Fig. 7 andmay include a magnet and coil =89 in the lead 90 to a contact 9! associated with whichis the movable conductor contact 92 pivoted at 93 and connected to the lead 8I. By pushing inwardly on the push-button 94 the movable switch contact 92 is shifted to engage the contact 9| and close the circuit to lead -8l, the magnet 83 by attracting a magnetic element on the contact 92 holding the switch closed until the circuit is broken, at which time the contact 92 will be shifted away from the has a curved stop shoulder !I at one end of an enlarged boss portion I02. When the operating handle I00 is in the upright position, as shown in full lines Fig. 2, the switch 92 may be closed because the lever 98 may swing into a position in front of the shoulder lllI. If, however, the handle I00 isin the horizontal or lower position, as shown in dotted lines Fig. 2, so that the brakes are in the released position, then the boss portion I 82 lies in front of the free end of the lever 98, as shown in dotted lines Fig. 2, and will prevent-swinging of this lever on its pivot. This will thus lock this lever and its connection 9'! in the dotted line position Fig. 2, which is the full line position of Fig. 7, and will prevent closing ofthe switch 92 to set the safety clamps so long as the hand1el00 is in the horizontal position and the brakes are released. It wlll therefore be impossible to set the clamps while the brakes are released or the car is in motion.

' There, is a lost motion connection between the arm 96 and the shaft or pivot -93 carrying the contact 82. This may be ajpin I03 carried, by the contact running in a slot I04 in the arm 96 which will operate when the switch 92 is closed to shift the arm 96 and the connecting link 0'! from the full to the dotted line positionin Fig. '7, or that is from the dotted to the full line position" in Fig. 2, in which position this arm 96 and connection 91 will be held by a spring catch I adapted to be released by a pull button I05. Catch I55 is adapted to engage a shoulder 9500- in arm 95. Thus operation of the pushbutton 94 will close the switch 912 and the arm 96 and the catch lever 98 will be shifted if the handle me is in the upper position and. the brakes applied, but as soon as the circuit is broken switch 92 may move to the open position under action of spring 95' as the pin I03 may slide in the slot its leaving the'arm 96 and lever 58 in-this slnfted position. 1

as it is held by the catch I05. However, as soon as the catch I05 is released by pulling the button H36 the weight of the parts-will again shift the arm 96 and catch lever 98 to the normal or lower position, which is the full line position of Fig. '7 and the dotted line position of Fig. 2. Thus through this interlocking control if the operator tries to shift lever-I00 from the upright full line position of Fig. 2 to the horizontal or dotted position without first releasing the catch I05 he will not be able to do so because the member '98 will be in front of shoulder IOI This will warn him that he has: not released the rail clamps. Therefore, before releasing the catch I05 he will. push in on the button 94' to shift switch contact 92'" to cause the solenoid controlled valve 68 to release the rail clamps, and he will then release the catch I05 to release the valve lever I00 to permit release of the wheel brakes. As it requires a pull on member I06 to release catch I05, instead of a push as in closing switch 92, there is little danger of the operator releasing catch I05 to release lever I00 before closing switch 92 to release the rail clamps. Therefore, although i it is possible to release the rail clamps before releasing the wheel brakes, the chances of doing so are remote, and in normal operation the brakes of the car will not be released until the rail clamps are released and raised to their carrying position. However, the clamps cannot be operated toclamp the rails until the brakes on the car have been set to hold the car.

In operation as the crane is brought to the proper location, the clamps of course are in the raised or inoperative position and the brake control valve handle I00 is in its lower or off position. Swinging this lever to the upright position supplies steam or air under pressure to the pipe I4 and the brake cylinder 63 to set the brakes. Shifting of the handle I00 to this full line position of Fig. 2 carries the raised boss portion I02 away from in front of the lever 98 and therefore unlocks the switch member 92 which may thus be operated by pushing in on the button 94 to close the circuit to the lead 8i through the insulated collector ring I03 mounted on the turning platform I2 and insulated therefrom and through a brush contact I09 connected to the lead BI and engaging this collector ring. The valve II at this time will be in its left hand position to supply pressure to the upper end of the cylinders 42 to retain the clamps in their upper or raised position. As the circuit is closed by the switch 92 and as in this position of the valve the switch '58 is closed, the circuit will be closed through the solenoid i3 shifting the valve II to the right or to the position of Fig. '7. As the valve reaches its right hand position stop 84 engages the switch 18 and opens the circuit. which therefore releases the switch 92 and permits it to swing to the open position. The valve H in this position permits fluid pressure to pass from the pipe 51 to the pipe linefill to shift the piston in cylinder 12 upwardly and through the operating mechanism 38 and 32, 26 and 23, to lower the clamps and set them in clamped position on the rails II, as shown in full lines Fig. 3. To release the clamps the operator merely again pushes the button 85 which again closes the circuit to the lead '51, out as the switch 19 is now closed current will pass through the soienoid i i to shift the valve 7! to the left or to the position to release the clamps. As the valvereaches the limit of its movement stop 85 engages'the switch to open it, thus breaking the circuit and ope- ..ng switch 92 while the stop 5 permits the switch I3 to close preparatory to thenekt operation; When the valve .l reaches its left hand position it shuts off communication from pipe 57 to pipe 59 permitting the pressure in pipe 5% to exhaust and supplying pressure to pipe m by which it is carriedto the upper end of the cylinder t2 toforce the piston therein and the cross head 20 downwardly to the dotted line position Fig. 3, which motion first releases or unclamps the clamps I5 from the rail and'then raises them to the inoperative position in which they are locked by any suitable means or by inserting pins 44 in the openings 43 in the rods 2i above the brackets 28. The locking lever 98 is still in front of the shoulder H to prevent shifting of the brake control handle lllil to the brake releasing position. However, the operator now by pulling on the button l 06 can release this by releasing catch l 65 so that it is shifted to the dotted line position Fig. 2'by the weight of the parts, thus releasing the brake control lever, and the operator can now swing it to the lower or horizontal position to release the brakes and permit the crane to be shifted to a new location. The brakes can be operated at any time except when the clamps are applied and locked to the rails.

It will be evident that while the clamps are set or clamped on the rail if the crane operator tries to lift too great a load, that is, a load beyond the normal capacity of the crane, such that it will tip the crane beyond the limit for which it is designed to tip for this load, the brackets 28 will be shifted to engage the stop nuts 29 and there fore put tension on the rod 2i and the correspending clamp. The nut 29 is normally set the proper distance away from the top of the bracket so that in normal operation and with normal loads there is no pull on the clamps, but if this normal load is exceeded so that the crane platform tips beyond the normal amount the strain is transmitted to the nut 29, rod 2! and the clamps and further tipping of the crane is therefore prevented. It will be clear from Fig. 3 that the pull on the clamp and rod 25 is a straight up and down pull, as indicated by the double arrow H0, and also that all the pull of the rod 2| is transmitted to the clamps through the pivot 59 so that none of this pull is transmitted through the operating mechanism 23, 26, 32, etc. Also when the crane tips under this overload the scale 45 and the cylinder 48 are shifted upwardly compressing the spring 58 and moving the contact 45 into engagement with the contact iii if the load limit for which these contacts are set is equalled or exceeded. This will thus immediately close the circuit through the indicator or alarm 55 and warn the operator in the cab that the allowable load limit for that inclination or radius of the boom has been equalled or exceeded and he should not, therefore, apply further load to the crane. This will prevent his applying suflicient load to the safety clamps to pull up the track rail.

When the safety clamp grips a rail the parts are in the positions shown in full lines Fig. 3. First downward movement of the piston in cylinder 42 carries the cross head 49 to the first or upper dotted position. This movement by swinging lever 32 raises member 26 moving the pivotal connection 25 upwardly in slot 21. This raises the links 23 and pulls the upper lever arms 22 inwardly to the dotted line position at the left of Fig. 3 shifting the jaws 26 outwardly away from the rail H and releasing the clamp. Further downward movement of the head 40 to the lower dotted position carries member 25 still higher as shown at the right hand portion of Fig. 3. Duringthis movement the pivot 25 by engaging the top of slot 2] raises the rod 2| and its head 29 carrying the jaws It with it to the dotted line position in the right hand portion of Fig. 3. This slides rod 2! upwardly in the bracket 28 as indicated. In setting the clamps the opera tion is reversed. Upward movement of the piston in cylinder 42 and head 40 firstlowers the member 26 permitting the rod 2| and head 20 to move downwardly to the full line position and the jaws and links to the dotted line position at the left hand portion of Fig. 3. Then further upward movement of head 40 moves member 26 and pivot 25 down further swinging the arms 22 outwardly and setting the jaws l6 about and under the tread flange l1 as shown in fulllines.

The car automatic coupler is indicated at I H with a coupling pin H2 connected to the lifting arm N3 of the operating rod I I4 operated in the usual manner by the handles I I5. It will be seen from the above that with this safety mechanism, which may be controlled entirely by the crane operator within the cab by simple operations, that he must first set the brakes of the car and then may set the safety clamps, which with ordinary caution will prevent him from lifting or attempting to lift loads beyond the designed capacity of the crane, which would be liable to tip the crane beyond the limit for which it was designed; that when the crane is to be shifted to a new location the safety clamps must first be released and raised to the inoperative or carrying position, and then the car brakes may be released to permit the crane to be shifted.

This device is merely a safety device. That is, when the crane is workingwithin the normal capacity for which the crane was designed there is no holding of the crane or car platform by this device. The safety gauge or indicator may be set as described for a given load and given inclination or angle of the crank boom and it indicates when the load reaches this limit. That is, it indicates when the operator is trying to lift over the proper load limit sothat he will not go beyond this with danger of lifting the track. But the clamps hold the wheelson the track and prevent the crane tipping over if he goes beyond this limit so that the two cooperate to keep the operation within safe limits. What might be a safe load with the boom steeply inclined and with the load on a small radius from the car might not be a safe load with the boom more nearly horizontal and the load at a greater radius. The pointer or contact 46 and stop 29 can therefore be set for the proper boom angle or load radius, and contact 5| shifting an amount depending on the load will coact with 46 to indicate when the desired limit has been reached. Therefore the device is primarily to keep the operator from overloading the machine and thus keep from tipping over the car. It thus insures safety by preventing overloading and tipping beyond given limits.

While the device is shown as applied to a locomotive crane this is merely for illustration as it is adapted for application on any crane or car traveling on rails where in use the load or other forces might tip the car over. While a fluid power device is shown for operating the clamps any other suitable type of power means may be employed, such for example as electrical or mechanical. Having thus set forth the nature of my invention what I claim is:

1. In a device of the character described comprising a car mounted to run on rails and including a body, a safety rail clamp mounted adjacent each of the opposite sides of the body, each clamp comprising jaws .to grip under the tread flange of a rail to prevent tipping of the car beyond a given limit and mechanism for setamen ting, releasing, raising and lowering the clamps, power means for operating said mechanism, manually operable control means for setting and releasing the brakes of the car, manually operable control means for the power means, and an interlocking connection between the brake con-.- trol means and the power control means includ ing means to prevent operation of the second manually operable control for setting of the clamps when the brakes are released;

2. In a device of the character described comprising a car mounted to runon rails and including a .body, a safety rail clamp mounted on said body comprising jaws to grip under the tread flange of a rail to prevent the car tipping beyond a given limit and mechanism for setting and releasing the jaws, power means for operating said mechanism, manually operable control means for setting and releasing the brakes of the car, manually operable control means for the power means, and an interlocking connection between the brake control means and the power control means including means to prevent operation of the second manually operable means for setting of the clamp while the brakes are released and means to prevent operation of the first manually operable means for release of the brakes while the clamp is set.

3. In a device of the character described comprising a car mounted to run on rails and including a body, a safety rail clamp mounted on said body comprising jaws to grip under the tread flange of a rail to prevent the car tipping beyond a given limit and mechanism for setting and releasing the jaws, power means for operating said mechanism, control means for setting and releasing the brakes of the car comprising a control lever movable between an on and an off position, control means for the power means, cooperating means on the brake control lever and connected with the power control means to prevent operation of the power control means to set the clamp when the brake lever is in the off position, and said cooperating means also arranged to prevent shifting of the brake lever to the off position while the clamp is in the set position.

4. In a locomotive crane comprising a car mounted to run on rails and including a body and rotatable platform thereon for the crane mechanism and cab, means for setting and releasing the brakes of the car including a brake cylinder, a fluid pressure supply pipe connected with said cylinder, a control valve in said pipe having an operating hand lever in the cab movable between on and off positions, a safety clamp mounted on said body including jaws adapted to clamp under the tread flange of a rail to prevent tipping of the car beyond a given limit, power mechanism to operate said clamp to clamp it on and release it from the rail including a cylinder, a pipe connection from said supply pipe to this cylinder, a control valve in said connection, means for controlling the latter valve located in the cab, and an interlocking connection between the latter control means and the brake control lever including means to prevent operation of said control means to set the clamp while the brake lever is in the off position and to prevent shifting of the brake lever to the off position when the clamp is in the set position.

5. In a device of the character described comprising a car mounted to run on rails and including a body, a safety rail clamp mounted on said body including a guide bracket secured to the body, a supporting rod slidable vertically in said bracket, a stop on the rod manually spaced abovethe'brac'ket tdengagextne bracket to I'I'lit upward movement thereof relative to the rod, a pair of jaws pivoted to th'e'lod and carri d thereby, said jaws being 'ad'apte td clam under the tread flange of a rail, pe er mchan connected with the jaws to joper'at'e' them'onlthell pivots to clamp and release the ram, and m nu: ny operable contrblmeanjs for the power j ie ch anism mounted on the body. I

6. In a device of the character described com= p s a ca mou ed t run f1 rai an i cluding a body, a safety rail lc larnp mounted on said bod including a guide bracket secured'totne body, an upright supporting rod slidable bracket having ahead, ma'nste limit upward movement of the bracket relative to the rod, a pair of levers pivoted to the head having jaws to engage under the tread flange of a rail and upwardly and outwardly extending arms, said head having an upright elongated slot above the pivot for said levers, links pivoted to the lever arms at their lower ends and connected at their upper ends by a pivot means slidable in said slot, an operative member connected to said pivot means, and power means for raising and lowering said member.

7. In a device of the character described comprising a car mounted to run on rails and including a body, a safety clamp mounted on said body to prevent tipping oi the car beyond a given limit comprising a pair of jaws adapted to grip under the tread flange of a rail, a supporting member on which the jaws are mounted, means for mounting said member on the body for limited vertical sliding movement relative thereto, and power means mounted on the body independently of said member connected with the jaws and said member to set and release the jaws and lift said member to raise the jaws above the rail, said power means having lost motion connection with the member to permit operation of the jaws before shifting of said member.

8. In a device of the character described comprising a car mounted to run on rails and including a body, a safety clamp mounted on said body to prevent tipping of the car beyond a given limit comprising a pair of jaws adapted to grip under the tread flange of a rail, a supporting member mounted for limited vertical movement on the body, a pair of jaws pivoted to said member having upwardly and outwardly extending arms, an upright guide in said member, links pivoted to said arms at their lower ends and to a pivot at their upper ends slidable in said guide and adapted to coact with the upper end thereof to lift said member, and power means connected with said pivot to shift the same to operate the jaws and shift said member.

9. In a device of the character described comprising a car mounted to run on rails and including a body, a safety rail clamp mounted on said body to prevent tipping of the car beyond a given limit comprising a supporting member mounted for limited vertical movement relative to the body, a pair of jaws pivoted to said member and adapted to grip under the tread flange of a rail, and means acting independently of movement of said member connected to said jaws adapted to swing them in opposite directions on the pivot both to clamp the jaws on and release them from the rail so that the entire pull from the car on the jaws is through said member.

10. In a device of the character described comprising a car mounted to run on rails and including a body, a safety rail clamp mounted on said body to prevent tipping of the car beyond a given limitcomprising a guide bracket on the body, a supporting member mounted to slide in said guide bracket, jaws on said member to grip under the tread flange of a rail, a limit stop on said member normally spaced above said bracket to be engaged thereby when the car tips beyond a certain limit, and an indicator comprising relatively movable members connected to the body and said supporting member and cooperating when the car tips to cause the bracket to engage said stop to indicate a given load has been reached.

11. In a crane comprising a car mounted to run 15 on rails and including a body, a safety rail clamp mounted on said' body to prevent tipping of the car beyond a given limit comprising a supporting member mounted for limited vertical movement relative to the body, means on the body to place a pull on said member when the body tips to said limit, jaws mounted on the member to grip under the tread flange of a rail, an adjustable'stop' carried by the body, a second stop connected with the supporting member to move therewith toward the first stop as the car tips, and means operated by coming together of said stops to indicate to the crane operator that a given load has been reached.

FREDERICK F. ZAVATKAY.

/f? CERTIFICATE OF' CORRECTION.

Patent No. 2,527,525. August 17, 1915.

FREDERICK F. ZAVATKAY.

It is hereby cert. led that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 52, for "clamps" read --c1amps-; page 5, first column, line 22, for "in" read -is--; page 5, second column, line 1, claim 5, for "manually" read --normally--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this ll th day of September, A. D. 1915.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

